31. At that time I still felt ______ my feet were cold and _______ my hands ached terribly.
| A．that; that | B．that; / | C．that; what | D．what; that |
These new measures will put many small businesses at __________ risk, so he must look for __________ way out.
| A．the; the |
| B．the; a |
| C．a; the |
| D．不填；a |
Once upon a time, a （n）__________ famous scientist said that life was not easy for any of us but first of all we should believe in ourselves.
| A．another |
| B．sure |
| C．some |
| D．certain |
He let me repeat his instructions __________ sure that I understood what was __________ after he went away.
| A．to make; to be done |
| B．making; doing |
| C．to make; to do |
| D．making; to do |
David couldn't tell __________ from far away whether the green traffic light meant going straight or turning left.
| A．on purpose |
| B．at random |
| C．in short |
| D．for sure |
-Are you a volunteer now?
-No, but I __________. I worked for the City Sports Meeting last year.
| A．used to |
| B．used to be |
| C．used to do |
| D．was used to |